Blade construction for elastic-fluid turbines.



H. T. HERR.

BLADE CONTRUCTION FOR ELASTIC FLUID TURBINES.

HIS ATTORNEY IN FACT HERBERT r. HERB, or rrrrsnonen', PENNSYLVANIA,ASSIGNOR TO THE wnsrrnenoUsE MACHINE COMPANY, A CORPORATION orPENNSYLVANIA.

BLADE CONSTRUCTION FOB, ELASTIC FLUI D TURBINES.

Taall whom it may concern:

Be it known that I, HERBERT T. HERB, a citizen of the United States, anda resident of Pittsburgh, in the county of ,Allegheny and State ofPennsylvania, have-made a new and useful Invention in Blade Constructionfor Elastic-Fluid Turbines,\of which the followingis a specification.

This invention relates construction and hasfor an object to produce newand improved means for shrouding and tying together the outer ends ofthe blades locatediin a row. This'and other objects I attain by means ofa blade construction embodying the features herein described, andillustrated in the drawings accompanying and forming a part of thisapplication.

In the drawings: Figure 1 is a fragmental, sectional view of a rotorelement of a turbine equipped with blading. embodying my invention; Fig.2 is a perspective view of a blade forming a detail of my invention, anddiscloses the tie memberreceiving slot formed across the outer end ofthe blade; Fig. 3 is a sectional view of a tie member, forming a detailof my invention, and discloses its shape before it is secured in placein the mounting slots formed inthe ends of the blades; Fig. 4 is aperspective view of several blades in the position they occupy whenassembled on a blade-mounting element.; the blades are shown inconnection with the tie member, which is shown crosssectioned at one endand broken away at the other; and Figs. 5 and 6 are each fragmentalelevations of blades equipped with integrally formed spacing pieces(shown in section) and illustrate two separate embodiments of myinvention. 7

It is desirable to provide a shroud for the outer or free ends of bladesof the impulse type; that is, for the ends of the blades locatedfarthest from the blade-mounting element. It is also desirable to tiethe outer ends of turbine blades together, since during the operation ofa turbine each blade is subjected to successive shocks due to the impactof the motive fluid and this tends to create vibrations in the blade. Bytying together the outer ends of the blades located in a row, eachblade-is caused to cooperate with the blades to which it issecured inresisting the vibration creating strains and the tendency for each bladeto vibrate'is to turbine blade next adjacent blade,

Specification of Letters Patent. Patented Dec, 21 1915.

Application filed May 14, 1914. Serial No. 838,538.

thereby largely overcome. I

In the drawings I have, for convenience of illustratiom'disclosed aturbine rotor pro vided with a circumferentially extending undercutgroove which is adapted to receive blades havlng specially formedbasesor mounting portions. It will, however, be understood that my inventionmay be employed in connection with the stationary as Well as therotating blades.

As illustrated in Figs. 1, 2, and 4:, each blade 7 consists of 'asubstantially crescent shape body portion, which is provided on one sidewith a concave Working face 8 and on the other side with a convexforward face 9. The mounting portion 10 of each blade is adapted to fitinto the blade-mount- -ing slot and also to provide means for spacingthe blades. In other words the. base pieces 10 of the blades not onlysecure the blades in place, but also insure a proper spacing of theblades. Each base piece cor- .responds in cross-section tothecross-s'ection of the blade-mounting slot in which it is located,and, as illustrated in Fig. 4, is adaptany means may be employed forspacing the blades at their bases or mounting ends.

Each blade forming a detail of my in vention is provided at its outer orfree end with a cover or spacing piece 11, which is adapted to cooperatewith the spacing pieces J 11,01 adjacent blades, in maintaining theproper spacing for the outer ends of the blades, in forming a cover orshroud for the row of blades and 1n providing means bywhich the outerends of the blades'are secured together. v

In the specific embodiment of my inven-' tion illustrated each spacingpiece 11 1s of substantially the same width as the blade on which it ismounted; it extends substantially at right angles to the curved workingfaces of the blade, and its front and rear faces are -each curved to thesame degree of curvature. With this arrangement the front face of eachpiece 1? engages and 'fits snugly against the rear face of the piece 11on the it being understood that,

between the blades.

spend in degree to that of the concave working face 8 or to that of theconvex forward face of the blade on which it is mounted. If desired, itmay be of any other degree of curvature or may even be'providedwithstraight or .angular.edges.. .In addition to this, the p1ece may belocated. in any desi ed posi on with relation to the blade;

that is,--it*1fia'v overhang the forward face only, or it may overhangthe concave work ing face only, or, as illustrated,it may be located inan intermediate 'positionon the blade, so thatitroverhan'gs'boththeforward and the rear working faces. x

-The outer face of each blade spacing piece cated that its endsregisterwith the adjacent 5 ential'slot adapted to receive a tie member.

ends of the slots formed in' adjacent pieces 13 for the outer ends ofthe-blades.

As illustratedyin Fig- 3, the tie member is' initially arch-shapeincross section,.and.is

- each blade and consequentlytie -the'outer gently.

4 I such length 'as to merelyflsecure groups of provided withpara'llel'lateral' sides.- In .-'ad-.

dition to this,'it'is of' su 'ch widththat it' is capable of beingfittedinto the eircumfer-f; ential slot 'formedby' the cooperatingslots. inthe outer face of'each of the pieces 11. After thestrip 13 is'inplace,.i t is flattened out, as shownin Fig. I;v is therebyincreased .inwidth and its parallel lateral f'acesaremoved to inclined positions{corresponding to the inclination of the undercut wall of the slot withwhich they enga e. this way themember 13 is positively secured to endsof the blades together and eliminates the TJOSSlbilltY of theirvibrating independan'annular row of blades, or it may -be of blades inan annular row together.

15 mayb ecured toitsenga 2,14: 5 by any suitable means,-such,f fi

. In Fig. have shownv an embodiment of; my inventlon in which thespacingTpiece 111? is provided on" its outer "face-"witlijfie .bvwelding, and'by'weldin'g Imeanby the ap-: pllcationof heat either withor without pres It will be understoodthatthe member 15,1ike'themember-13, 6b. v faces. of adjacent bladesengages-the outer securedto'each' of the; blades engaged by it.

. In Fig. 7 I'have illustrated a still fur,-' .ther modification ofmyjinvention in ,vvhich the "spacing piece 11 formed at the outer iendof the blade-,i7is arranged so that it is fifiilicapable of 1bei ng"positively secured to :two

What I claim' is; 1. Incombination The strip 13 may extendfclear aroundands positively welding.

For the purpose of' preventing the-blades.

v or pieces 11 from moving in a longitudinal direction, relatively tothe "tie-member or strip, I preferably employ means for posi-.

tively. locking the strip and each spacing piece together. This may beaccomplished by distorting one or both edges of the strip so that it ispressed into gripping e'ngage-* ment'with theadjacent edgesof thestripillustrated in Fig. 4, I have distortedthe strip by means of acenter punch, or similar tool, by driving the punch between. eachreceiving slot formed in each piece; As

edge of the strip. 13 and the adjacent edges of the slot 12,so that-boththe strip andthe (pieces 11' are distorted and are pressed into 11illustrated, is provided with acircumferv entially extending undercutslot 12, so 10- looking or positive engagement' with-each While I havedescribed several modifications of I ny invention, it 'willbe'; apparentforth. by the appended claims. 1

with a blade-mountin element, a""row 'ofblades mounted on said element,a 'spacing piec'e for the outer end y invention, as set of'eacl blade,said spaeing'pieces cooperatto form an organized shroud for the row ofblades-and a .tie'ymember' mounted in a circumferentially ex'tndedgroovein the organi'zed shroud.

2. In combination"with -iaiblade mounting 1 element, aow of bladesmounted on the ele-' ment, aspacing piece for; the outer end of 'eachblade integrallyformed oneach blade,

said spacing pieces cooperating to form. an

organized shroud" forthe-zrow. of. blades, an'dk a circumferentiallyextending .tie. member n positixtelysecuredto each spacing piece-so.as'to prevent relative motion between the '--member and the piece.longitudinally of: the h 3. Inv combination with a turbine blademounting element, a row of blades mounted on the element, a spacingpieceforthe outer v V ends of the-blades'integrally formedon' each. I

.' blade, said spacing. piecesfcooperatil?flto .form a' shroud for, theouter ends o blades, and a tie member locatedina'groove formed on theshroud and'poslt vely'locked to eachblade. J

' 4. In combination'with turbine, ablade i mounting element, a-row ofblades mounted 2'5 formed onthe outer end of each bladefthe on (said.element, a: spacing piece integrally lit 3 blades in said row being 'so-located-'.on"said element that the spacing. pieces coiioperate to forma shroud for the row and a he memher for the outer ends of the b1adesextefid- 'formed on the outer end of each blade, the

blades being so located in each row that the spacing pieces cooperate toform a shroud for the row,- and a tie member for the outer ends of theblades extending along a circumferentially extending slot formed in theperipheral face-of the organized shroud and Welded to each spacing pieceengaged there- 6. In combination with a turbine blade carrying element,a row of blades mounted on the element, spacing pieces for theouter endsof the blades cooperating to form an organized shroud for the row ofblades, and a tie member mounted in a circumferentially extending grooveformed in the shroud.

7 In combination with a turbine blade carrying element, a row of bladesmounted on the element, spacing pieces for the outer ends ofthe bladescooperating to form an organized shroud for the row of blades, and a tiemember mounted in a circumferentially extending groove formed in theshroud and positively secured to each of the blades of the row.

In testimony whereof, I have hereunto subscribed-my name this 12th dayof May,

HERBERT T. HERB.

Witnesses:

C. W. MoGlmu,

E. W. MCCALLISTER.

